xtreg postestimation, what is xb doing ?

[anne claire]

Dear all,

i am estimation an FE panel estimation xtreg y x, fe.
When predicting my fitted values: predict yhat, xb does NOT give me the same results than gen yhat2= _cons + _b[x]*x, nor gen yhat2= _b[x]*x
can you explain me why ?
thanks in advance
ac

(nb: i also checked , predict yhatu, xbu, predict u, u)

[Phil Schumm]

When predicting my fitted values: predict yhat, xb does NOT give me the same results than gen yhat2= _cons + _b[x]*x

The system variable _cons when used directly is equal to the number 1, which is not what you want here; instead, you want the value of the intercept from the fitted model. Try

gen yhat2= _b[_cons] + _b[x]*x

instead.